The invention relates to a device for folding an gas bag.
Inflatable gas bags in vehicles serve to protect occupants from impact in a collision, sensors being used to sense vehicle deceleration exceeding a critical value and to activate, via an electronic control means, an inflator providing a sufficiently large volume of gas to fill the gas bag within a very short period of time. The gas bags are arranged in the vehicle so that direct impact of the occupant with parts of the vehicle body is prevented in a collision.
For accommodating the gas bags in the vehicle they are folded together to a minimum volume. The folding has to be designed in a way the instant inflation of the gas bag will not be obstructed or delayed. In the case of a head-on collision of the vehicle the gas bags need to be inflated within 30-40 ms, in a side-impact collision no more than 10 ms are available therefore.
Various methods are known for folding the gas bags in place, all of which have the disadvantage that relatively complicated devices are needed for satisfactory folding in place and that the folding procedure itself is highly time-consuming.
The invention is based on the object of proposing a device for introducing a gas bag into a pot-shaped receiving container having a installation opening at the bottom for the arrangement of an inflator, this device being structured substantially simpler, permitting shorter job timing intervals for folding in place and is easily adaptable to differing installation conditions for the gas bag. In addition the device is adapted to be integrated in automated production lines and to operate reliably with no problem over a long working period requiring minimum maintenance.
This object is achieved by means of a device for introducing an gas bag into a pot-shaped receiving container with an insertion opening for insertion of the gas bag and an installation opening at the bottom for the arrangement of an inflator is provided. The device comprises a tubular housing having a cross-section adapted to the insertion opening of the receiving container, and an axially reciprocating ram arranged in the housing and serving for introducing the gas bag into the receiving container. It has been found out that by means of such a device an gas bag initially accommodated elongated can be compacted into the desired package shape simply by advancing the ram without it being necessary xe2x80x94 as usual hitherto xe2x80x94 to implement highly specific folds in a predetermined time sequence. By interaction between the force exerted via the ram and the restoring forces of the fabric material of the airbag every arbitrary fold of the gas bag individually not predictable, is achieved in the space available in the pot-shaped receiving container. It could be verified by extensive trials that an airbag folded in this way can be deployed with no problem within the time available for instant inflation. It will readily be appreciated that the straightforward axial displacement of a ram in a tubular housing is much easier to achieve than a defined folding routine for which a much more complicated device is needed. In the device in accordance with the invention the gas bag simply needs to be introduced into the tubular housing, the tubular housing inserted into the pot-shaped receiving container and the gas bag then compacted by extending the ram.
The object mentioned above is also achieved by means of a method for folding a gas bag is provided, wherein the gas bag is introduced into a tubular housing, wherein a body is introduced into the gas bag as a dummy for an inflator intended to be mounted later, and wherein the gas bag is folded around the body. Concerning the advantages achieved with such method, reference is made to the explanation given above with respect to the device according to the invention.
Advantageous further aspects and variants of the invention read from the sub-claims.